Rafter square



March 11, 1952 R. CRUICKSHANK RAFTER SQUARE Filed Feb. 16, 1951 ATTORNEYS cu Patented Mar. 11, 1952 UNITED STATESPATENT OFFICE RAFTER SQUARE Roy Gruickshank, West Branch, Mich.

Application February 16, 1951, Serial No. 211,285

2 Claims. 1

This invention relates to a rafter square, and more particularly, has reference to a rafter square of improved design, whereby the rafter square can be adjusted for a selected pitch to be given a rafter, after which the adjusted setting can be used for making all necessary markings upon the rafter, thereby to mark the rafter for all the cuts to be made therein.

The main object of the present invention is to provide a generally improved design of rafter square, that will be capable of being adjusted to the desired setting speedily and with ease, and which will be capable of use with equal facility.

Another important object is to provide a rafter square that will be rugged, will be composed of a minimum of parts simply arranged, and that will be adjustable for any desired pitch.

Still another object is to provide a rafter square so formed that when set for the proper pitch, its various ruling or marking edges will be automatically related to permit marking of the rafter for both end cuts thereof, as well as for notching of the rafter intermediate its ends.

With the foregoing and other objects in View which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts, hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

Referring to the drawings,

Fig. 1 is a side elevational view of a rafter square formed in accordance with the present invention, the dotted lines indicating a preliminary position thereof, and the full lines indicating a position to which the rafter square may be adjusted, the rafter square being illustrated in position upon a rafter to be marked.

Fig. 2 is an enlarged section on line 2 2 of Fig. 1.

Fig. 3 is a fragmentary perspective view illustrating the connection of one of the ruling blades to the adjustable arm of the device.

Referring to the drawings in detail, I designates a rafter to be marked, and it will be understood that this rafter can be of any desired size. The device formed in accordance with the present invention includes an elongated flat base plate 2 overlying a guide flange 3 and secured permanently and fixedly to said guide flange by rivets 4 or equivalent fastening means. As may be noted from Fig. 2, the guide flange 3 is adapted to be engaged against one side edge of the rafter I.

A link 5 is pivotally connected at 6 to one end of the base plate 2. At the other end of the base plate, said base plate is pivotally connected to one end of an elongated adjustment arm 6' formed with a longitudinal slot 1.

Pivotally connected at 8 to the other end of link 5 is one end of an elongated connecting arm 9, that is pivotally connected at its other end, as at I0, to an intermediate portion of the adjustment arm 6.

As a result, it will be noted that the base plate, link, connecting arm, and one end portion of the adjustment arm, cooperate to define a parallelogram. By reason of the several pivotal connections, adjustments can be made as to the angularity which the link 5 and adjustment arm 6 bear to the base plate.

Pivotally connected at H to the other end of the adjustment arm is an elongated arcuate segment l2 having a longitudinal slot 13, through which extends stud l4 secured to an intermediate portion of the connecting arm 9, wing nut l5 being threaded upon the stud and bearing against the segment for the purpose of clamping the segment to the connecting arm in selected positions of adjustment.

A ruling blade i6 is provided with a stud l'i extending through slot 1, the stud having a wing nut similar to the wing nut l5 for the purpose of clamping the ruling blade fixedly to the adjustment arm 6 in selected positions of adjustment longitudinally of said adjustment arm. The ruling blade I6 is of right angled shape, and is provided with a guide flange I8 at one end, whereby the base portion of the ruling blade may be retained at right angles to the adjustment arm 6' at all times.

The segment [2 is provided with a scale l9, any graduation of Which is adapted to be brought into register with an index marking 20 provided upon the connecting arm 9. The scale has graduations corresponding to the desired pitch to be given the rafter.

In use, the rafter square might be initially positioned as shown in dotted lines in Fig. 1. Thereafter, the wing nut I5 is loosened, and the arcuate segment adjusted relative to the connecting arm, for the selected pitch. The segment is then clamped fixedly to the arm. It will be noted that in making the desired adjustment of the segment relative to the connecting arm, the angularity of the members 5 and B to the base plate will be automatically adjusted, and the ruling blade will of course also be automatically adjusted, since it is carried by said member 6,

After the rafter square has been adjusted for pitch, the rafter can be marked at both ends, and can also be marked for an intermediate notch or birds mouth out, this last marking being made along the edges of the ruling blade 16, and in the desired marking for notching of the rafter whereby it may be seated upon the usual plate, not shown.

Thus, the left hand edge of the link as seen in Fig. 1, can be used as a ruling. edge whereby to mark the rafter for cutting of one end, as for example, the lower end thereof. The left hand edge 2| of the ruling blade will have been automatically related to the ruling edge of the link 5, for marking of the cut to be made at the upper end of the rafter, that is, the ridge cut.

Without changing the setting of the rafter square, the rafter square can be adjusted to a desired location upon the rafter, after which the edge 2| and edge 22 of the ruling blade 16 are properly positioned for marking the rafter for notching thereof.

What is claimed, is:

1. A rafter square comprising a base plate adapted for engagement with one edge of a rafter to be marked; a link and adjustment arm parallel to each other and each pivotally connected at one end to opposite ends of the base plate; a connecting arm pivotally connected at one end to the other end of the link, and pivotally con.- nected at its other end to an intermediate portion of the adjustment arm; an arcuate segment pivotally connected at one end to the other end of the adjustment arm, and having a pivotal connection to the connecting arm, said segment being adapted for clamping to the connecting arm in selected positions of adjustment of the segment relative to'the connecting arm; and a ruling blade of right angled configuration attached to said adjustment arm.

-2. A rafter square comprising an elongated base plate; a guide flange rigidly secured to said base plate and adapted to engage one edge of a rafter to be marked; a link pivotally connected at one end to one end of the base plate; an elongated adjustment arm pivotally connected at one end to the other end of the base plate, said link and adjustment arm being parallel to each other; a connecting arm parallel to the base plate and connected at opposite ends to the other end of the. link and to an intermediate portion of the adjustment arm; a ruling blade of right angled configuration having a base portion extending at right angles from said adjustment arm, said base portion of the ruling blade being connected to the adjustment arm for adjustment longitudinally of the adjustment arm; means for clamping the ruling blade to the adjustment arm in selected positions to which the ruling blade is adjusted; and an arcuate segment pivotally con nected at one end to said adjustment arm, said segment having its other end extending across the connecting arm and pivotally connected to REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 133,086 Donaldson Nov. 19, 1872 2,090,835 Gardham Aug. 24, 1937 

